spice up vs season

spice up is not a noun while season is a noun.

Word	Noun	Adjective	Verb	Adverb
spice up	No	No	Yes	No
season	Yes	No	Yes	No

As verbs, season is a hypernym of spice up; that is, season is a word with a broader meaning than spice up:

Other hypernyms of spice up include flavor, flavour.

spice up (noun)	season (noun)
	one of the natural periods into which the year is divided by the equinoxes and solstices or atmospheric conditions
	a recurrent time marked by major holidays
	a period of the year marked by special events or activities in some field

spice up (verb)	season (verb)
make more interesting or flavorful	make healthy
add herbs or spices to	make more temperate, acceptable, or suitable by adding something else
	lend flavor to